PROJECT SUMMARY Autosomal recessive polycystic kidney disease (ARPKD) and other hepato-renal fibrocystic diseases (HRFD) are relatively rare recessive disorders, but constitute an important set of childhood nephropathies. Rare disease research requires greater collaboration than the efforts in common diseases where patient resources are routinely available and large repositories can be built locally. For the HRFD, experimental studies would be well served by case accrual that coordinates collection of clinical data, bio-specimens (DNA and tissues) and mutational information. The centralization and sharing of clinical and genetic information, as well as bio-materials, can provide a critical impetus for more rapid progress by the research community. In this competitive renewal, we will continue to compile baseline and longitudinal clinical information in our HRFD Clinical Database; expand our bio-materials (DNA and tissue) repositories; and deploy new strategies to identify genetic mutations in ARPKD and other HFRD patients, including new tools to interpret PKHD1 missense variants. Clinical and genetic data, as well as patient bio-specimens, will be drawn from tertiary care centers throughout the Americas (North, Central, and South). Finally, we will utilize the learning management system established in our CTSA-funded program to establish a multi-modality resource for our expanding portfolio of HRFD-related educational information and tools. Our goal for this renewal application is to acquire a sufficient volume of clinical data, biological specimens, and genomic information in a centralized resource to accelerate discovery research in human HRFD and integrate the resulting data in an enabling platform for developing new, targeted interventional strategies, assessing genotype-phenotype correlations, and identifying new disease genes by our Investigator User Base, as well as other members of the research community.